# -*- coding: utf-8 -*-
class A(object):
    def f(self):
        print('A')    
class B(A):
    def f(self):
        print('B') 
        super(B, self).f() 
class C(A):
    def f(self):
        print('C')
        super(C, self).f()
class D(B,C):
    pass

d = D()
d.f()   